A new study has linked consumption of plant-based ultra-processed foods with poor health outcomes, but is a backlash against meat alternatives missing the point? Nick Hughes reports.
Ultra-processed foods (UPFs) are back in the spotlight – not that they’re ever far away from it these days.
This time, it is plant-based UPFs facing specific scrutiny after a study that found an association between their consumption and a greater risk of ill health reignited the debate over the role of plant-based meat alternatives in healthy diets.
Funded by the World Cancer Research Fund and published in The Lancet Regional Health – Europe journal, the study analysed data on the dietary intake of 118,397 adults as captured by the UK Biobank programme.
Using the NOVA classification – a system of grades from one to four that compares the degree of processing of food and drink products – it found that a higher intake of energy from non-ultra-processed plant-based foods like fruit, vegetables and pasta was associated with lower risks of cardiovascular disease (CVD), while higher intake from plant-based UPFs was associated with higher risks.
Researchers stressed that there was no association between consumption of all plant-based foods and CVD risk, while consumption of all UPFs, including meat products, was associated with higher risk.
They concluded that a higher energy intake from plant-based foods may only bring about better health outcomes when largely based on minimally processed foods, while a higher intake of plant-based UPFs may have detrimental effects on health. Guidelines promoting diets based on plant-based foods should emphasise not only the reduction of meat, red meat, or animal-sourced foods, but also the need to avoid all UPFs, the authors added.
Misleading coverage
The results of the study achieved widespread media coverage, some of which emphasised the negative health impacts of eating plant-based meat alternatives. This has caused disquiet among some experts who caution that a focus on meat substitute products has the potential to mislead the public.
As well as meat alternatives, the study categorised plant-based UPFs as including packaged breads, biscuits, pastries and cakes, margarine and other spreads, and confectionery – all technically plant-based foods but not necessarily foods people commonly associate with the term plant-based (or “plant-sourced” as the study refers to them). In fact, just 0.2% of the total energy intake from study participants came from ultra-processed meat alternatives, yet these received a disproportionate amount of coverage in media write-ups of the findings.
The Science Media Centre, whose aim is to provide accurate and evidence-based information about science and engineering through the media, asked a range of scientists and academics for their views on the study and how the results had been presented. Experts were mostly impressed by the quality of the research, including the large sample size, detailed dietary information and conclusions that were backed up by the data available. Yet they also expressed concern that people could get the impression that the focus of the study was on meat alternative products.
Dr Hilda Mulrooney, reader in nutrition and health at London Metropolitan University, said: “I […] don’t think when people think of ‘plant-based’ they think of bread, cereals etc. I imagine they think more of meat, fish and dairy product alternatives.” She added that: “The greatest contributor to the ultra-processed plant-based foods are not meat alternatives but bread, pastries, buns, cakes, and biscuits, which arguably are not good markers of a plant-based diet, since many people consuming meat will also be consuming those products.”
Peter Scarborough, professor of population health at the University of Oxford, cautioned that it was “very difficult to conclude from this paper that plant-based meat alternatives are bad for your health”.
Reluctant regulators
The study and the consequent debate over its findings gets to the heart of one of the main issues surrounding UPFs – that evidence consistently shows associations between consumption of UPFs and negative health outcomes, however causality cannot be easily demonstrated.
This helps explain why governments and public health bodies have so far been reluctant to target consumption of UPFs as a distinct food group, with current regulation (relating to advertising restrictions for example) instead focused on the nutrient profile of individual products.
The noisy, and often confusing narrative surrounding UPFs has prompted the UK’s Food Standards Agency (FSA) to tentatively enter the debate. In May, it published advice for consumers in which it stated that while there is a correlation between poorer health outcomes and diets that are high in UPFs, “we still don’t know whether it is because these foods are unhealthy because of how they are made, or if it’s because a large majority of processed foods are high in calories, saturated fat, salt and sugar”.
The agency noted that while some (but not all) UPFs are high in fat, sugar and salt, it’s hard to establish whether this is the sole reason why consuming lots of them can lead to poorer health, or whether there are additional negative health impacts from other factors like palatability, energy density, or how some ultra-processed foods are made. “These are some possible causes, but they have not yet been fully explained by the science,” it said.
The government’s expert scientific committee, the Scientific Advisory Committee on Nutrition (SACN), has been similarly equivocal in its position. In an evidence review published in July last year, SACN said more research was needed before it could draw any firm conclusions about whether UPFs cause poor health, despite finding associations between increased consumption of UPFs and an increased risk of health issues such as obesity, chronic diseases like type-2 diabetes, and depression.
Evidence grows
The FSA pointed to a high volume of research currently underway in many countries, including the UK, which is likely to improve our understanding of UPFs within the next few years.
Evidence that proves causality between UPF consumption and ill health may prove a tipping point for policy intervention should it eventually emerge, although critics of UPFs would have governments act immediately.
Another recent addition to the evidence base is research from the University of Central London (UCL), published in the British Journal of Nutrition, which found that UPFs contain more calories, fat, saturated fat, sugar and salt than minimally-processed foods – but that not all UPFs are unhealthy.
Researchers set out to investigate whether food processing information could be a useful indicator of what is healthy to eat. They compared data on the level of processing in commonly eaten foods to the nutritional information found on front-of-pack labels and found that UPFs (as classified under NOVA) had worse nutritional scores, with greater levels of energy, fat, saturated fat, sugar and salt than minimally-processed foods. Processed foods, one step below UPFs on the NOVA scale, also scored badly on front-of-pack labelling criteria, but were not as high in energy or sugar as UPFs.
Yet the results also indicated that not all UPFs are unhealthy based on nutritional information. The research team gave the example of a meat-free mince product, which might be colour-coded green for fat, saturated fat and sugar under a traffic light label, and amber for salt, but would also be considered ultra-processed if it had more than five ingredients, many of which are additives.
Samuel Dicken, first author of the study from UCL Division of Medicine, stated: “There is a clear overlap between the healthiness of food, front-of-pack labelling and the level of food processing.” However the study’s lead author, Dr Adrian Brown, a specialist dietitian from UCL Division of Medicine, added: “At the moment, things aren’t so clear cut as to say all UPFs are bad and there is a risk of confusing people about what is healthy to eat.”
That risk is real according to consumer survey data. Since August 2023, UPF has been one of the top three concerns raised by consumers surveyed in the FSA’s monthly consumer insights tracker. End of year results published last month showed that UPF was the second greatest concern for the public behind only food prices and ahead of food inequality.
This combination of public anxiety and a rush to research their harms suggests there is little chance of UPFs – and the businesses that produce them – escaping the spotlight any time soon.
Fascinating article, thank you!
I do though wonder if we are maybe pursuing the wrong point a bit here. A lot of the science seems to be trying to chase down the evidence that UPFs are intrinsically unhealthy.
It feels likely (though as yet unproven) that at least some are. Might another lens be to ask which foods are MORE healthy than others? It would surely be difficult to argue that a food without added fillers, emulsifiers, anti-oxidants, and preservatives is anything other than healthier than one that does?